Pressure head assembly

ABSTRACT

A pressure head assembly for holding work of different thicknesses against displacement while permitting travel of the work therebeneath and having a multiplicity of elements slidably suspended for upright reciprocation relative to one another and common pressure-responsive means for resisting movement of the elements away from said work; said elements being relatively narrow transversely and being disposed in a plurality of contiguous rows with the elements of each row being staggered with respect to the elements of adjacent rows whereby said elements overlap, the contiguous transverse relationship of said elements permitting the slidable confinement of short as well as long pieces of work and the overlapping relationship and transverse narrowness of said elements permitting the slidable confinement of narrow as well as wide work pieces.

[ Dec.9,1975

United States Patent [1 1 Cromeens Primary ExaminerRoy Lake PRESSURE HEAD ASSEMBLY [75] Inventor:

Jeff Y. Cromeens Mesquite Assistant ExaminerNeil Abrams Attorney, Agent, or FirmJoseph H. Schley; Thomas L. Cantrell [73] Assignee: Industrial Woodworking Machine Co. Inc., Garland, Tex.

Mar. 15, 1974 [57] ABSTRACT A pressure head assembly for holding work of different thicknesses against displacement while permitting travel of the work therebeneath and having a multi- [22] Filed:

21 Appl. No.: 451,451

plicity of elements slidably suspended for upright reciprocation relative to one another and common pressure-responsive means for resisting movement of the elements away from said work; said elements being relatively narrow transversely and being disposed in a plurality of contiguous rows with the elements of each 144/249 R, 249 B, 249 A, 242 R, 242 B, 267

[ References Cited row being staggered with respect to the elements of UNITED STATES PATENTS adjacent rows whereby said elements overlap, the contiguous transverse relationship of said elements permitting the slidable confinement of short as well as long pieces of work and the overlapping relationship and transverse narrowness of said elements permitting the slidable confinement of narrow as well as wide work pieces.

4XXBB 4 277 66 2222 4// 19944 .66 22 r m 5 a m mam t n sme SS eu nk ca u Pm HSVSS 38 73 03556 99999 HHHHH 32623 1 l 026 38056 20659 245 7 J 2223 5 Claims, 6 Drawing Figures U.S Patent Dec. 9, 1975 Sheet 1 01 3 3,924,668

US. Patent Dec. 9, 1975 Sheet 2 of3 3,924,668

US Patent Dec. 9, 1975 Sheet 3 of3 3,924,668

PRESSURE HEAD ASSEMBLY BACKGROUND OF THE INVENTION Pressure head assemblies are in more or less common use for holding wood pieces or other work of different thicknesses against displacement relative to a support during conveyance of the work transversely of the linear dimension thereof. l-Iolddown devices of this type have consisted of a plurality of individual elements or shoes, usually overlapping linearly, suspended for upright reciprocating and/or canting relative to one another and constantly urged downwardly or toward said work by pressure-responsive means. Heretofore, the shoes of these devices have had insufficient amplitude of movement to accommodate work of appreciable variation in thickness. Also, ithas been necessary to vary the construction of the devices more or less in accordance with the length and width of the work pieces.

SUMMARY OF THE INVENTION The novel pressure head assembly of this invention is adapted to hold work, such as wood pieces, or lumber, of different lengths, widths and thicknesses against displacement with respect to a support during conveyance of the work transversely of the linear dimensions of its separate pieces. The assembly has a plurality of individual elements or shoes reciprocally mounted and constantly urged into positive engagement with the work regardless of variation in length, width and thickenss thereof within feasible limits, said elements being disposed in contiguous rows with the elements of each row being in substantial alignment with one another and being staggered or offset relative to the elements of the other rows whereby each element of each row overlaps elements of said other rows to provide a continuous surface for bearing against said work in opposed relation to its support. The work-engaging elements of each row are in closely adjacent nonoverlappin g relationship and are suspended independently for upright straightline reciprocation with respect to one another whereby said elements may be of generally rectangular configuration without restricting the relative movement thereof and/or impairing the slidable confinement effi ciency of the pressure head assembly. In addition to being arranged in transverse close proximity, the elements or shoes are of narrow width relative to their length so as to facilitate the use of a common or single pressure-responsive means for urging said elements into work-engaging position as well as to make possible minimum transverse dimension or width of the assem bly. Although particularly adapted for use with short work pieces, which are difficult to handle, it is readily apparent that the assembly is capable of movably confining long work pieces as well due to the positive work engagement of its holddown elements resulting from the reciprocal nontiltable mounting, transverse stagger ing or overlapping, narrow width and generally rectangular configuration thereof together with the closely adjacent nonoverlapping relation of adjacent elements of each row. Also, this transverse staggered relationship, insures that each portion of each element of each row constantly overlaps portions of the elements of the other rows. It is a further noted that each element or shoe is of sufficient length to provide ample surficial contact with the common pressure-responsive means for actuation thereby.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of a pressure head assembly, constructed in accordance with the invention, mounted on a woodworking machine,

FIG. 2 is a back side elevational view, partly insection, of the pressure head assembly,

FIG. 3 is a front end elevational view of said assem- DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawings, the numeral 1 designates a pressure head assembly embodying the principles of the invention and having an elongate, generally rectangular, hollow housing or head 2 slidably mounted on a woodworking or similar machine 3 (FIG. 1) in overlying, parallel, spaced relation to a substantially horizontal bed or table 4. An endless conveyor 5, having suitable upstanding cleats or lugs 6 at spaced intervals for contact with the lateral margins of wood pieces, lumber or other work (not shown) of narrow width relative to length, extends longitudinally of the inner margin of the table 4 in vertical alignment with the pressure head 2. The latter includes a pair of elongate, upright, parallel side plates or walls 7, which have reduced longitudinal extensions or flanges 8 at the upper marginal portions of their ends, and angular end plates or walls 9, 10 connecting the side plates and their flanges as well as a horizontal coextensive top plate or wall 11 secured between the upper margins of said plates and flanges (FIGS. 2-4). Manifestly, the plates or walls 7, 9, 10, 11 of the pressure head coact to form a coextensive downwardly opening rectangular chamber of much greater length than width.

As shown at 12 in FIG. 2, the lower margins of the infeed or lead end portions of the side plates 7 may be relieved so as to be slanted or inclined upwardly and outwardly and thereby prevent binding of the work upon its entry beneath the pressure head assembly 1. It is noted that the angular end plates 9, 10 include horizontal or transverse medial flanges underlying the .side plate extensions 8 with upright flanges upstanding and depending from opposite extremities thereof, the depending flanges of the infeed end plate 9 having less upright or vertical dimension than the leading upright margins of the side plates.

A suitable bracket assembly 13 (FIG. 1) upstands from the top plate 11 of the head 2 for adjustably mounting the pressure head assembly on the machine 3 to permit variation of its elevation relative to the table 4. Preferably, a pair of elongate, rectangular, guide brushes 14 project horizontally and longitudinally from the lower marginal portion of the infeed end of the front or outer side plate of the pressure head, being supported by an elongate flat bracket 15 secured to said plate, so as to depend therefrom for engaging the work as it is fed, whereby the travel of said work is resisted sufficiently to dispose the pieces thereof in perpendicular relation to the conveyor 5. If desired, a safety shield 16 may be provided at the infeed end of the conveyor in overlying spaced relation to the brushes 14 for actuating a stop switch (not shown) in the event pieces of work are forced upwardly by overcrowding or cocking thereof. Although subject to variation, the safety shield 16 may include a suitable bracket 17 pivotally mounted on the top plate 1 1 of the head 2 so as to project longitudinally therefrom and having a biased or spring-pressed guard plate 18, which is normally upright, pivotally suspended from its outer end in spaced relation to the guide brushes.

For engaging and preventing displacement of the work as it is conveyed along the table past the machine, a multiplicity of independent pressure elements or shoes 20, 30, 40 (FIGS. 2-6) are mounted for upright reciprocation within the chamber of the pressure head 2 and depend therefrom. The shoes 20, 30, 40 are disposed in contiguous, horizontal, parallel rows 21, 31, 41, respectively, as best shown in FIGS. 3 and 4, whereby the shoes of each row are in close proximity or substantially slidable contact with the shoes of adjacent rows. Also, each of the rows 21, 31, 41 has its shoes aligned longitudinally and in end-to-end contiguous or substantially abutting relationship as shown most clearly in FIGS. 4-6. In order to provide a continuous bearing surface longitudinally of the pressure head assembly, each of the rows has its aligned shoes staggered or offset relative to the shoes of the others of said rows, particularly the shoes of immediately adjacent rows, whereby said shoes overlap transversely of the pressure head and the work is in constant contact with at least two of said shoes at all times irrespective of the width of said work.

Each of the shoes of the rows 21, 31, 41 is of relatively narrow transverse width or thickness and of generally rectangular configuration, being of greater upright or vertical than horizontal or longitudinal dimension and having the lower margin of its infeed or lead end portion relieved so as to provide an inclined or slanted surface 23, 33, 43 and thereby facilitate riding of the work beneath said shoes. For the same purpose, an elongate toe or extension 24, 34, 44 projects longitudinally from the lower marginal portion of the outer or leading end of each of the infeed or lead shoes, designated by the numerals 22, 32, 42, and an upwardly and outwardly inclined or slanted bottom surface 25, 35, 45, respectively, is coextensive with each extension or toe and at least a portion of the lower margin of its respective shoe.

An upright or vertical slot or elongate opening 26, 36, 46 (FIGS. 1, 2, 5 and 6) extends transversely through the upper portion of each of the shoes for receiving one of a plurality of cylindrical pins 50 to slidable suspend said shoes within the chamber of the pressure head 2, the side plates 7 of the latter having complimentary openings 51 for supporting the ends of the pins. Each pin 50 is common to all of the rows 21, 31, 41 so as to extend through one of each of the slots 26, 36, 46 of the respective shoes -22, 30-32, 40-42. In order to stagger the shoes of adjacent rows, the slots of each row are offset relative to the slots of adjacent shoe rows. For example and as illustrated in FIGS. 5 and 6, the slots 26 of the front or outer, row 21 may be disposed adjacent the leading edges of the shoes 20, 22 and the slots 36 of the center or intermediate row 31 may be formed in the outfeed or tail marginal end portions of the shoes 30, 32, with each of the shoes 40, 42 of the rear or inner row 41 having its slot 46 medially of its upright margins. Accordingly, each of the shoes 20, 22 overlaps the rear one-third of each of the shoes 30, 32 and the front two-thirds of each of the shoes 40, 42, while the rear two-thirds of said 30, 32 and the front two-thirds of said 40, 42 overlap one another. Obviously, the exact relationship may be varied so long as each portion of each shoe of each row overlaps portions of the shoes of both of the other rows. As a result, the toe 34 of the center or intermediate row infeed shoe 32 projects to the greatest extent and the leading upright margin 37 of said shoe rides against the depending flange or leg of the angular end plate 9.

Bearing surfaces for the leading upright margins of the infeed shoes 22 and 42 are provided by rectangular spacers 27 and 47 (FIGS. 2-5) fastened to the aforesaid end plate flange, the spacer 27 being wider linearly due to the greater distance of said shoe 22 from said depending flange and the height of both spacers being less or not more than the upright or vertical dimension of the leading upright margins of the side plates 7 as well as said flange so as to prevent interference with the reciprocal or sliding movement of said shoes.

Similar spacers 38 and 48, relatively wide and narrow respectively, are secured to the depending flange of the outfeed or tail end plate 10 of the pressure head for guiding the reciprocation of the tailmost shoes 30 and 40 as shown in FIGS. 2, 4 and 6. Due to its offset relationship, the trailing upright margin of the tailmost shoe 20 rides against the aforesaid depending end plate flange. In order to assist in guiding the reciprocal movement of the shoes 20-22, 30-32, 40-42, a suitable short linear pin 52 projects transversely and perpendicularly from the lower portion of the leading upright margin of each of said shoes except the lead or infeed shoes 22, 32, 42 for loose slidable confinement in an upright opening or slot 53 formed in the lower portion of the contiguous trailing upright margin of each of said shoes except the tailmost. It is noted that the slots 53 are of relatively short length so that the trailing shoes are lifted when the immediately adjacent leading shoes are raised by the work sufficiently to expose the inclined or slanted bottom surfaces 23, 33, 43 of said trailing shoes, whereby the flat upright front margins of the latter are never exposed to said work. As shown by the numeral 54, both of the upper corners of each of the shoes 20, 22, 30, 32, 40, 42 and the inner upper corners of the spacers 27, 38, 47, 48 may be chamfered or bevelled.

For constantly urging the aforesaid pressure elements or shoes transversely outward or downwardly relative to the pressure head 2, a substantially coextensive pressure-responsive member 55 is mounted in the upper portion of the chamber of said head in overlying relation to said shoes and comprises an elongate sleeve or tube 56 of suitable elastic material. The tube may be substantially flat or elliptical in cross-section and has its ends closed, such as by suitable clamps 57, (shown in broken lines in FIG. 2) which, if desired, may be fastened to the undersides of the end portions of the top plate 11 of the head. A suitable inlet fitting 58 is provided in one end of the tube 56 and is adapted to depend through the transverse medial flange of the angular end plate 10 at the outfeed terminus of the pressure head and may be suitably secured to said flange. Air or other pressure fluid is adapted to be supplied to the inlet fitting 58 for inflating the tube and maintaining its engagement with the inner or top ends of the shoes. Preferably, a flat strip or band 59 of flexible material is interposed between the shoes and tube 56 so as to more uniformly distribute the force of the pressure fluid in said tube and prevent damaging and/or undue wear of the latter resulting from the continual reciprocal movement of said shoes.

From the foregoing, it is readily apparent that the pressure head assembly is of extremely narrow width so as to be particularly adapted for use in movably confining short pieces of lumber or other work, while still being capable of holding down work of many times the length of the short pieces. In order to illustrate the narrowness of the assembly, the pressure elements or.

shoes may be approximately five eights of an inch or less in thickness whereby the entire width of said assembly may be in the range of 3 inches or minus. Due to the transverse contiguous relation of the shoes and the continuous overlapping or staggered relationship of at least two of said shoes, it is obvious that work pieces as short as 1 inch and only a fraction of an inch in width may be movably confined during travel.

The foregoing description of the invention is explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction may be made, within the scope of the appended claims, without departing from the spirit of the invention.

I claim:

1. A pressure head assembly for holding discrete work pieces of different thicknesses, widths and lengths against displacement while permitting travel of the work pieces therebeneath including:

a pressure head elongated longitudinally of the direction of travel of the work pieces,

a multiplicity of relatively narrow elements slidably mounted in the underside of the pressure head and depending therefrom for upright reciprocation relative thereto and to one another,

pressure-responsive means in said pressure head overlying the elements for operative engagement therewith for resiliently urging said elements into engagement with the work pieces,

said elements being disposed in a plurality of contiguous rows extending longitudinally of said head with the elements of each row being staggered relative to the elements of adjacent rows whereby each portion of each element of each row overlaps portions of said elements of the other rows to provide a continuous bearing surface for the work pieces,

a plurality of means extending transversely of said pressure head for slidably suspending said elements,

each of the suspending means being common to one element of each of said rows for slidably supporting said elements independently of the other elements of the same row,

each of said elements common to the same suspending means having independent connection therewith so as to be reciprocable relative to its commonly supported elements.

2. A pressure head assembly as defined in claim 1 wherein the plurality of suspending means comprises pins supported by the pressure head and upright elongate openings in the elements through which the pins extend.

3. A pressure head assembly as defined in claim 1 including coacting means mounted on and loosely connecting adjacent elements of each row to limit movement of said elements relative to one another.

4. A pressure head assembly as defined in claim 1 wherein the elements of each row are contiguous and disposed in substantial alignment with one another,

each element being substantially rectangular and of narrow width transversely of its row whereby the combined width of the contiguous rows is relatively narrow,

the length of each element longitudinally of its row being sufficient to permit said element to constantly overlap at least one each of the elements of each of the other rows.

5. A pressure head assembly as defined in claim 1 wherein each of said elements is substantially rectangular and of narrow width transversely of said pressure head whereby the combined width of said contiguous rows relative to their length is narrow to permit the movable confinement of work pieces of narrow width and short length as well as the confinement of the end portions of longer work pieces extending transversely of the direction of travel thereof,

the elements of each row are contiguous and disposed in substantial alignment with one another,

the length of each element longitudinally of its row being sufficient to permit said element to constantly overlap at least one of each of the elements of each of the other rows. 

1. A pressure head assembly for holding discrete work pieces of different thicknesses, widths and lengths against displacement while permitting travel of the work pieces therebeneath including: a pressure head elongated longitudinally of the direction of travel of the work pieces, a multiplicity of relatively narrow elements slidably mounted in the underside of the pressure head and depending therefrom for upright reciprocation relative thereto and to one another, pressure-responsive means in said pressure head overlying the elements for operative engagement therewith for resiliently urging said elements into engagement with the work pieces, said elements being disposed in a plurality of contiguous rows extending longitudinally of said head with the elements of each row being staggered relative to the elements of adjacent rows whereby each portion of each element of each row overlaps portions of said elements of the other rows to provide a continuous bearing surface for the work pieces, a plurality of means extending transversely of said pressure head for slidably suspending said elements, each of the suspending means being common to one element of each of said rows for slidably supporting said elements independently of the other elements of the same row, each of said elements common to the same suspending means having independent connection therewith so as to be reciprocable relative to its commonly supported elements.
 2. A pressure head assembly as defined in claim 1 wherein the plurality of suspending means comprises pins supported by the pressure head and upright elongate openings in the elements through which the pins extend.
 3. A pressure head assembly as defined in claim 1 including coacting means mounted on and loosely connecting adjacent elements of each row to limit movement of said elements relative to one another.
 4. A pressure head assembly as defined in claim 1 wherein the elements of each row are contiguous and disposed in substantial alignment with one another, each element being substantially rectangular and of narrow width transversely of its row whereby the combined width of the contiguous rows is relatively narrow, the length of each element longitudinally of its row being sufficient to permit said element to constantly overlap at least one each of the elements of each of the other rows.
 5. A pressure head assembly as defined in claim 1 wherein each of said elements is substantially rectangular and of narrow width transversely of said pressure head whereby the combined width of said contiguous rows relative to their length is narrow to permit the movable confinement of work pieces of narrow width and short length as well as the confinement of the end portions of longer work pieces extending transversely of the direction of travel thereof, the elements of each row are contiguous and disposed in substantial alignment with one another, the length of each element longitudinally of its row being sufficient to permit said element to constantly overlap at least one of each of the elements of each of the other rows. 